Apparatus for control of fluidoperated pumps



July 25, 1961 D. E. MARQUIS 2,993,447

APPARATUS FOR CONTROL OF FLUID-OPERATED PUMPS Filed Nov. 17, 8

FIG. 2

INVENTOR. D.E. MARQUIS BY M FIG. 3

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POWER OIL PRODUCED O|L& EXHAUST POWER OIL A TTORNEYS United StatesPatent 2,993,447 APPARATUS FOR CONTROL OF FLUID- OPERATED PUMPS Duane E.Marquis, Bartlesville, 0kla., assignor to Phillips Petroleum Company, acorporation of Delaware Filed Nov. 17, 1958, Ser. No. 774,249 11 Claims.(Cl. 10346) This invention relates to apparatus for control offluidoperated pumps. In a more particular aspect the invention relatesto apparatus for automatically controlling the rate of flow of operatingof power fluid for driving a fluidoperated pump unit.

The invention is especially applicable to the operation of a hydraulicsubsurface pump unit in connection with the recovery of oil from oilwells. It is obvious, however, from the ensuing description that theapparatus can be employed in other services.

In pumping oil from a well it is conventional practice to employ ahydraulic or fluid-operated subsurface pump unit well below the groundlevel and submerged in the oil to be pumped. Such a pump has a fluidmotor which is operated by power oil pumped from the surface down to thefluid motor. The oil in the well is pumped to the surface through aproduction tubing. Ordinarily, great depths are involved, and a numberof conditions not readily detectable at the surface can afiect theoperation of the pump adversely. In the past the rate of operation ofthe fluid motor, and therefore of the pump has been controlled at thesurface merely by regulating the power oil rate at the surface. Theoperation of such pumps are adversely affected by conditions such asfluctuations in the pumping load which can cause the pump to race whenthe load lightens and to incur hydraulic shock when the load returns.For instance, there should always be a certain minimum head of fluidabove the pump inlet in the well in order to provide a suflicient netpositive suction head to prevent vaporization within the pump itself.Other conditions which sometimes exist to affect the pump load includethe entrainment of gases with the oil into the pump suction, withsubseqent discharge of gases into the production tubing, thus lesseningthe head of the discharge side of the pump and reducing the workrequired by the pump, with resultant increase in the rate at which thepump operates unless the supply of power oil is throttled. Anothercondition which can cause a change in the pump load is occasionalpumping of slugs of water together with oil, thus also changing thepressure on the discharge side of the pump when the Water enters theproduction tubing.

Therefore, an object of the present invention is to provide a governorfor controlling the rate of flow of power fluid to a fluidoperation pumpin which the rate of operation of the pump is regulated in accordancewith the load or work required by the pump. It is also an object of theinvention to control the rate of operation of a fluidoperated pump inaccordance with the hydraulic head of fluid to be pumped on the suctionof the pump.

Other objects, as well as advantages and aspects, of the invention willbecome apparent from the accompanying disclosure and the description ofthe appended drawings.

The invention will be better understood by reference to a description ofthe drawings, of which FIGURE 1 is a general view of a well showing awell casing, submerged hydraulic pump, supply tubing for supplying powerfluid, a governor for controlling the rate of said power fluid, andproduction tubing for conveying produced oil and exhaust power oil tothe surface. FIGURE 2 is an elevation in detail of one embodiment of mygovernor, while FIGURE 3 is an elevation of another embodiment of thelower valve control mechanism of my governor shown in FIGURE 2.

Referring now to FIGURES 1 and 2, 10 is a well casing in which isdisposed a tubing 11 for conducting produced fluids and exhaust poweroil to the surface. Also disposed inside the casing 10 is a secondtubing string 12. Within tubing 12 there is positioned a hydraulicsubsurface pump unit 13 of conventional design. The pump unit of thisembodiment is of the free type, that is, the pump can be pumped down thetubing to its position as illustrated, and by reversing the direction offlow of power oil, it can be pumped back to the surface. An example ofsuch a pump unit is shown in volume 2 of the 1957 Composite Catalogue ofOil Field Equipment and Services, published by World Oil, Houston,Texas, at page 2896.

Inserted in the tubing string 12 above pump unit 13 is my governor forcontrolling the flow of power fluid to the pump 13, generally designatedat 20 in FIGURE 1. The flow controller or governor is contained withinan enlarged section 21 of the tubing string 12. This enlarged section isfrequently called a receiving sub. Within the receiving sub there islocated a sliding sleeve 22. This sleeve has a plurality of ports 23.These ports register with ports 24 in the receiving sub at any time theflow controller is in its operating position, that is, the position asshown. When ports 23 and 24 are in registry, there is communicationbetween the annular space surrounding the tubing string and the interiorof the tubing. O-ring seals are provided at 25 to seal between thereceiving sub and the sleeve 22. These seals are disposed so as toisolate ports 24 and 23 from fluid above and below the point at whichthese ports enter the interior of the tubing. Receiving sub 21 isprovided with a shoulder 26. This shoulder restricts the upward movementof sleeve 22 as will be hereinafter discussed. Receiving sub 21 has asecond shoulder 29 that restricts downward movement of sleeve 22. Nearthe lower end of sleeve 22 is a recess 27 and a third shoulder 28. Thisrecess and shoulder cooperate with dogs 32, -33 to be discussedhereafter. Receiving sub 21 must be separable in order to install sleeve22. This is conveniently done by providing threads as at 19 forseparating the two sections of sub 21 in order that sleeve 22 may beinserted.

The control valve proper is contained within housing 31. Housing 31 hasattached to its lower end two sets of latches or dogs. These are shownat 32 and 33. Latches 32 and 33 are biased by coil springs 41 to urgethem outwardly. When the flow controller assembly is pumped down tubingstring 12, latch 32 engages recess 27 and shoulder 28, thus forcingsleeve 22 downwardly and causing ports 23 and 24 to register. Sleeve 22striking shoulder 29 of receiving sub 21 prevents further downwardmovement and thereby retains ports 23 and 24 in registry.

Dogs 32 are held in a retracted position (shown by dashed lines inFIGURE 2) during running in operations by means of retaining ring '42.Retaining ring 42 is supported by a plurality of posts 43 which in turnare attached to ring or collar 44. Collar 44 serves as a mount for dogs33. Collar 44 is attached to a smaller collar 45 by means of shear pins46. Shear pins 46 are made of a soft steel or even of aluminum, copper,or brass so that they will shear at a predetermined stress. Pins 47which hold dogs 33 to collar 44 are of a stronger material. Collar 45 isurged upwardly by compression spring 47 which rests on lower housing 48.Lower housing 48 is supported by center tube 51.

The flow controller assembly 20 is installed in the well tubing abovethe hydraulic pump 13. With the free type pump, this is done byinserting the pump at the surface and allowing it to fall by gravity toits operating position, or by pumping it into place by pumping power oildown the tubing string 12.

After the pump is inserted the flow controller 20 is inserted. The fiowcontroller falls by gravity or is pumped into position. The lower dogs33 are urged outwardly by springs 41 but because of the angle at whichthese dogs extend, the flow controller is permitted to progress down thetubing string. After dogs 33 pass shoulder 28 of sleeve 22, thecontroller is then ready for placing in its operating position. This isdone by reversing the flow of power oil momentarily so that oil flowsdown tubing 11 and up tubing 12. The flow controller will then tend tomove up but dogs 33 prevent this. Additional pump pressure then causesthe controller to move up slightly and this compresses spring 47 forcingcollar 45, collar 44, posts 43 and retaining ring 42 downwardly withrespect to dogs 32. Dogs 32 are thereby released to engage recess 27 andthe upper face of shoulder 28. Flow of power oil is then returned to thenormal direction and sleeve 22 is forced downwardly until shoulder 28rests on shoulder 29 at which time ports 23 and 24 are in registry.During the time power oil is being pumped in the reverse direction,upwardly in tubing 12, the fiow controller 20 is prevented from beingreturned to the surface because dogs 33 engage shoulder 28 of sleeve 22and sleeve 22 cannot rise higher than shoulder 26 of the receiving sub21, It is important during the reverse flow of power oil that only smallpressures be used since excess pressure will shear pins 46 and cause thedevice to pump upwardly out of the tubing.

To remove the flow controller from the wells all that is necessary is toreverse the flow of power oil so that oil is pumped down tubing 11 andback to the surface via tubing 12. This will unseat the pump 13 andcause it to rise upwardly to strike against the bottom end of the flowcontroller. Retrieving a bottom hole hydraulic pump in this manner iswell known in the art and needs no further explanation here, except tostate that power oil is not forced down into the well bore below pump 13because standing valve 15 FIGURE 1) prevents such flow. When pump 13strikes the lower surface of the flow controller, additional pressure isapplied and dogs 33 force collar 44 down. A further increase in pressurewill shear pins 46 because collar 45 cannot move down along tube 51further than stop ring 52. When pins 46 shear, collar 44 will fall intothe bottom space of lower housing 48,. and at the same time dogs 33 willbe fully retracted so that they cannot prevent additional upwardmovement of the flow controller. Continued pumping of the power oil willthen pump the flow controller and the pump 13 to the surface.

When flow controller is installed in its operative position, ports 23and 24 are in registry. Power oil is pumped down tubing 12 through theconduits in the flow controller and down to pump 13 where the producedoil is mixed with the exhaust power oil for return to the surface viatubing 11. As oil from the producing formation enters the well bore, itrises to some point above the flow controller in annular space16. Theheight to which the oil rises will be dependent on the productivity ofthe well and on the rate at which the oil is pumped out of the well.Obviously, it is desirable to operate pump 13 at a high speed when alarge amount of oil is available in space 16 and at a slower rate whenonly a small amount of oil is available. Valve 65, 66 of my flowcontroller will regulate the pumping rate in accordance with the amountof oil available for pumping. The amount of oil available for pumping isin direct proportion to its height in space 16 and, for that reason, thehydrostatic head of the column of oil is used to regulate the rate offlow of power oil and hence the speed of the hydraulic pump.

.The hydrostatic head created by the column of oil in space 16 isapplied to the means for positioning valve 65, 66- via" ports- 24'- and23. Ports 23 communicate with annular groove 53 in body 31. Annulargroove 53 is confined by packing rings 53a which can be O-rings, chevronpacking or any other suitable material. Groove 53 communicates withpassageway 55 which terminates in cylinder 56. In the embodiment shownin FIGURE 2, there is disposed within cylinder 56 a piston 57 which ismounted on valve stem 61. A spring 62 urges piston 57 downwardly.Suitable packing is provided at 63 and 64 to make a seal between thevalve stem 61 and the upper and lower portions of cylinder 56. It isdesirable, although not absolutely necessary, that the space insidecylinder 56 above piston 57 be charged with a gas under pressure. Anysuitable dry gas can be employed but nitrogen is readily available andis especially suitable. If a gas charge is employed, suitableconnections for introducing the gas (not shown) are provided.

From the preceding, it will be seen that piston 57 will move upwardly incylinder 56 in proportion to the hydrostatic pressure exerted on theunderside of the piston by the column of fluid in annular space 16. Aspiston 57 moves, valve stem 61 will move and, thus, the opening betweenValve head 65 and seat 66 will be a function of the same hydrostaticpressure. As shown in FIGURE 2, it will be noted that all pressureforces on valve stem 61 are balanced except the differential created bythe hydrostatic head of oil and the bias created by the gas charge andthe spring 62.

Below valve seat 66 in housing 31, there is a passage 67 within tube 51.Communicating with passage 67 is a passage 71. Passage 71 connects withconduit 71a, which in turn communicates with passage 71b communicatingwith a cylinder 90. Disposed in cylinder is compression spring 91 andpiston 92. Piston 92 is connected to another piston 93 by valve stem 94.Piston 93 is also a valve member because it has a conical lower surface95. This conical'surface mates with valve seat 96 in partition 101.Surrounding piston 93 is cylinder 97. There is also a passageway 98through valve stem 94 that extends to the top of piston 93. Thus, piston93 acts as a dash pot to regulate rate of movement of the valve.

The elements just described, cylinders 90 and 97, pistons 92 and 93,valve surface 95, valve seat 96 and valve stem 94 comprise a loadresponsive regulating valve. By load responsive is meant the conditionwhereby the bottom hold hydraulic pump engineis required to performgreater or lesser amounts of work depending upon operating conditions inthe well bore that are independent of the liquid level in annular space16. For example, if a considerable amount of gas is produced With theoil, some of this gas will be entrained in the produced oil being pumpedto the surface through tubing 11. As the oil and gas approach thesurface, the gas expands and frequently this expansion literally blowslarge volumes of oil from the tubing. When this occurs, the fluid levelin tubing 11 may be, for a short time, many hundreds of feet down fromthe surface. The result of this is that there is a reduced back pressureon the subsurface hydraulic pump and less work required by the pumpengine. In a similar manner, if the well produces varying amounts ofwater, it is possible under some circumstances that the column of fluidin tubing 11 will be principally water and the hydraulic gradient willbe much greater than if oil only i being pumped. Under thiscircumstance, the pump engine is required to perform more work. Thischange in the Work load' on the pump engine is reflected in a change inthe pressure of the hydraulic'oil power supply in passage 67. Sincepassage 67 is in direct communication with the underside of piston 92,this pressure is utilized to regulate the opening between valve surfaceand valve seat 96. Thus, the valve is responsive to pump loads,

Power oil from a surface pump unit is pumped down tubing 12 by a surfacepump (not'shown) through ports 102 in housing 31 and ports 102a incylinder 97 through the load responsive valve 95, 96, space 103, liquidlevel responsive valve 65,66 and thence down passage 67 to the ydraulicsubsurface pump 13. Exhaust power oil and produced oil are forced uptubing 11 to the surface. My flow controller regulates the flow of poweroil in accordance with the hydraulic head of oil available in space 16as well as in accordance to the load on the pump as affected byvariations in the back pressure exerted through tubing string '11.

In FIGURE 3 is shown another embodiment of the control means for theliquid level flow control valve 65, 66. As shown here, the biasingspring 62 and piston 57 have been replaced by a gas charged bellows 83.Nitro gen gas under pressure is a convenient and readily available gas.Provision for charging the bellows is made by filling connector 81, 82with integral ball check valve. Alternately, the bellows can contain aspring biasing the valve closed.

While the flow control valve assembly 29 can be retrieved by pumping itback to the surface as has been previously described, it can also beinstalled or removed by wire line techniques. These techniques are wellknown in the industry and it is believed that no detailed explanation isrequired here. A fishing neck 111 is provided at the top of body 31. Asuitable installation and/or removal tool can be attached to the fishingneck of the flow control valve. To install the valve, the assembly 'willbe lowered by wire line to the receiving sub 21 and raised slightly torelease dogs 32, thus locking the valve in position. After this, thesetting tool is released and removed. To remove the valve, a removaltool is lowered through tubing 11 to engage the fishing neck 111.Pulling upward with su ficient force will shear pins 47 allowing collar44 to fall downward thus retracting dogs 33. With dogs 33 retracted, thevalve can then be withdrawn.

As will be evident to those skilled in the art, various modifications ofthis invention can be made or followed in the light of the foregoingdisclosure and discussion without departing from the spirit and scope ofthe disclosure or from the scope of the claims.

I claim:

1. A governor for controlling the flow of power fluid for operation of afluid-operated unit which is adapted to be submerged in a body of liquidcomprising, in combination; a housing defining a passage for supplyingsaid power fluid to said unit; a first valve in said passage throughwhich all power fluid must pass in traversing said passage; a secondvalve in said passage through which all power fluid must also pass intraversing said passage, downstream from said first valve and arrangedin series therewith; pressure actuable means responsive to a pressuredifferential across said second valve for operating said first valve;and pressure responsive means exposed to the fluid pressure exerted uponthe exterior of said housing for operating said second valve.

2. A governor of claim 1 wherein said first valve has a dashpotoperatively associated therewith.

3. A governor of claim 1 where said second valve includes a valve seatand a moveable valve member adapted to engage said valve seat to closesaid passage, and wherein said pressure responsive means comprises acylinder closed at both ends, a valve stem slideably extending throughsaid cylinder and through both ends thereof in a fluid-sealedrelationship and connected at one end with said moveable valve member, apiston in said cylinder, said valve stem being rigidly aflixed to saidpiston at an intermediate point in said cylinder, a compression springin said cylinder on one side of said piston urging said valve to aclosed position, and a passageway communicating with said cylinder onthe other side of said piston, said passageway communicating at itsother end with said body of liquid to be pumped.

4. A governor of claim 3 wherein said cylinder contains a gas underpressure on the same side of the piston containing the compressionspring.

5. A governor of claim 1 wherein said first valve includes a valve seatand a moveable valve element adapted to engage said first valve seat toclose said first valve and wherein said pressure responsive means foroperating said second valve comprises a closed vessel, a valve stemextending through one wall of said vessel in a slideable, fluid-sealedmanner and connected at one end with said moveable valve element andconnected at the other end with a compressible diaphragm containedwithin said closed vessel, said closed vessel being in fluidcommunication with said body of liquid to be pumped.

6. In a fluid-operated pumping apparatus for use in wells, thecombination of: a fluid-operated pump submerged in well fluid in a well;a first conduit for conveying power fluid for operating said pumpdownwardly through the well to said pump; a second conduit connectedwith the outlet of said pump for conveying pumped liquid upwardlythrough said well; governor means in said first conduit adapted tocontrol the rate of flow of power fluid therethrough, said governormeans including a first valve in said first conduit through which allpower fluid must pass in traversing said first conduit, a second valvein said first conduit through which all power fluid must also pass intraversing said first conduit fluid, said second valve being downstreamfrom said first valve and arranged in series therewith, pressureactuable means responsive to a pressure differential across said secondvalve for operating said first valve, and pressure responsive meansexposed to the fluid pressure of said well fluid in said well foroperating said second valve.

7. A governor for controlling the flow of power fluid for operation of afluid-operated unit which is adapted to be submerged in a body of liquidcomprising, in combination; a housing defining a passage for supplyingsaid power fluid to said unit; a first valve in said passage throughwhich all power fluid must pass in traversing said passage; a secondvalve in said passage through which all power fluid must also pass intraversing said passage, down stream from said first valve and arrangedin series therewith; pressure actuable means responsive to a pressuredifferential across said second valve for operating said first valve.

8. A governor of claim 7 wherein said first valve has a dash potoperatively associated therewith.

9. A governor of claim 7 wherein said first valve includes a valve seatand a moveable valve element adapted to engage said first valve seat toclose said first valve, and wherein said pressure actuable meanscomprises a valve stem connected to said moveable valve element, acylinder, a piston in said cylinder, said piston being connected to saidvalve stem, and said piston being exposed on one side to fluid pressureexisting upstream of said first valve and on the other side to fluidpressure existing downstream from said second valve.

10. A governor of claim 9 wherein said cylinder contains a compressionspring on said other side of said valve tending to urge said first valvetoward an open position.

11. A governor of claim 10 wherein said moveable valve element isassociated operatively with a dashpot for damping the action of saidmoveable valve element, said dashpot being in fluid communication,through an opening in said valve element and said valve stem, with thefluid downstream from said first valve.

References Cited in the file of this patent UNITED STATES PATENTS2,266,356 Coberly Dec. 16, 1941 2,589,668 Coberly Mar. 18, 19522,637,276 Coberly May 5, 1953 2,703,585 Coberly Mar. 8, 1955

